Figure REF  shows the radio-optical overlay of 3C390.3 using the DSS optical image and the uGMRT 621 MHz contours. The elliptical host galaxy is clearly seen in this image. The 621 MHz image of 3C390.3 is presented in Figure REF . Here the total intensity radio contours are superimposed on by EVPA vectors in red. The synthesized beam is \(7.54^{\prime \prime } \times 4.85^{\prime \prime }\)  with a position angle (PA) of \(-44^\circ \) . The rms noise in the total intensity image is 950 \(\mu \) Jy beam\(^{-1}\)  and polarized intensity image is 200 \(\mu \) Jy beam\(^{-1}\) . We observe a typical double radio source with lobes and terminal hotspots in 3C390.3. Overall, the fractional polarization in the north-western lobe and hotspot is higher than that in its south-western lobe and hotspot. Transverse EVPA vectors were seen in a jet segment entering the northern hotspot implying parallel B-fields, assuming optically thin emission. These could represent the poloidal B-field component associated with the radio jet. The EVPA vectors then appear to rotate in the hotspot region. This could suggest that the B-fields are compressed due to shocks in the hotspot region [1]}, [2]} (see Figure REF ). The EVPA rotation further implies a rotation of the jet head itself.
[3]} have suggested that if a supermassive binary black hole system possesses a radio jet, it will show a long-term precession, which can potentially be observed as morphological features in radio images. Along with the wide terminal hotspot and jet-lobe misalignment (hotspots are seen at one edge of the lobe in 3C390.3 rather than in the centre), the rotation of B-field vectors along the northern hotspot in our image is consistent with jet precession. This would be consistent with the results found by [3]} in their 5 GHz image for 3C390.3 and may support the binary black hole hypothesis for it. Jet precession could however also occur due to accretion disk warping due to radiation instabilities or other effects [5]}. Alternatively, our image could be consistent with jet bending, possibly due to strong jet-medium interaction.
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